1. Field of the Invention
This invention relates to sound reproduction. More particularly, this invention relates to high fidelity loudspeaker systems capable of faithfully reproducing sound signals over a wide range of frequencies.
2. Prior Art
A great variety of loudspeaker designs have been proposed for high quality sound reproduction, and a number have gone into commercial use. Typically, modern systems utilize different speakers for different segments of the sound spectrum, e.g. a so-called "woofer" for bass, a midrange speaker for intermediate frequencies, and a so-called "tweeter" for the very high frequencies.
The use of "motional feedback" wherein the motion of the cone in an electrodynamic loudspeaker is transduced, inverted, and fed back to the summing point of a control loop is well known. The object of such control has been to provide an improvement of the bass reproduction by the loudspeaker and a reduction in acoustic wave form distortion.
It is generally accepted that loudspeakers of sufficient size to produce adequate bass do not reproduce well at high frequencies. Breakup of the cone into standing waves, as well as beaming and other directional effects cause poor sounding reproduction to result when a "full range" loudspeaker is attempted. For these reasons, in high fidelity speaker systems a separate mid-range and possibly a tweeter are used even when motional feedback is applied to the woofer.